Charge splitting resistive layer for a semiconductor gamma camera

Abstract

An improved semiconductor gamma camera is disclosed. The gamma camera includes a p-i-n semiconductor diode which detects the presence and energy of gamma radiation from a source. Typically the source is radioactive material in a patient organ which is detected and then interpreted by a doctor while diagnosing the condition of that organ. The detector includes an improved electrical connection technique to allow the p-i-n diode to be connected to electronic circuitry necessary to provide spatial and energy information. In the improved camera first a passivation layer is deposited on both faces of the p-i-n diode and then a resistive layer is applied to form a reliable easily reproduced electrical contact to the junction. These two layers in combination prevent foreign matter from contacting the semiconductor material comprising the detector while providing interconnection to the electronic circuitry.

What is claimed is: 
     
       1. A semiconductor gamma camera detector comprising: (a) a portion of semiconductor material with two surfaces, a first surface including an n doped region and a second surface including a p doped region; said doping configured with the semiconductor material to form a p-i-n diode with a depletion region for producing electrical charge in response to radiation impinging on the semiconductor material;   (b) a passivation layer substantially covering at least some of said doped regions and defining openings extending therethrough in communication with portions of said doped regions;   (c) a resistive layer covering at least a part of said passivation layer and extending through said passivation layer openings to contact said regions; and   (d) electrical connections attached to said resistive layer.   
     
     
       2. The gamma camera detector of claim 1 wherein said two surfaces comprise substantially parallel opposed surfaces of said material. 
     
     
       3. The gamma camera detector of claim 2 wherein the n doped region comprises a first set of linearly oriented parallel bands and the p doped region comprises a second set of linearly oriented parallel bands, said sets oriented orthogonal to each other. 
     
     
       4. The gamma camera detector of claim 3 wherein a said passivation layer is disposed over each of said opposed surfaces and the resistive layer extends through the passivation layer to contact each of said doped bands. 
     
     
       5. The gamma camera detector of claim 4 wherein the resistive layer on each surface has two electrical connections positioned near opposed edges of said resistive layer. 
     
     
       6. A solid state gamma ray detector comprising: (a) a portion of intrinsic semiconductor material having at least one regionally doped surface;   (b) a passivation layer overlying at least a portion of the doped surface and having an opening communicating with a doped region of the surface, and   (c) a resistive layer overlying the passivation layer and communicating with the doped region via said passivation layer opening.   
     
     
       7. A solid state gamma ray detector comprising: (a) a portion of intrinsic semiconductor material having two generally opposite faces, a first of said faces having regionally p-doped parallel strips, a second of said faces having regionally n-doped parallel strips, said p-doped strips and n-doped strips being generally mutually orthogonal;   (b) passivation material overlying each of said opposite faces and defining openings communicating with each of a plurality of said doped strips on its said respective face;   (c) a resistive layer overlying at least a portion of the passivation material overlying each face, each resistive layer including resistive material communicating with said doped strips by way of said passivation layer openings, and   (d) electrical contact attached to each of said resistive layers.   
     
     
       8. A semiconductor gamma camera detector comprising: (a) a portion of semiconductor material with two surfaces, a first surface including an n-doped region and a second surface including a metal rectifying contact region; said region forming a p-i-n diode with a depletion region for producing electrical charge in response to radiation impinging on the semiconductor material;   (b) a passivation layer substantially covering at least some of said doped and surface barrier regions and defining openings extending therethrough in communication with portions of said regions;   (c) a resistive layer convering at least a pair of said passivation layer and extending through said passivation layer openings to contact said regions; and   (d) electrical connections attached to said resistive layer.